Json Web API 复杂参数属性全部为空

我有一个Web API服务调用，可以更新用户的首选项.不幸的是，当我从jQuery ajax调用调用这个POST方法时，请求参数对象的属性总是null(或默认值)，而不是传入的内容.如果我使用REST客户机(我使用Postman)调用相同的精确方法，它的效果会非常好.我不知道我做错了什么，但我希望有人以前见过.这相当简单...

Here's my request object:

public class PreferenceRequest
{
    [Required]
    public int UserId;

    public bool usePopups;
    public bool useTheme;
    public int recentCount;
    public string[] detailsSections;
}

下面是我在UserController类中的控制器方法:

    public HttpResponseMessage Post([FromBody]PreferenceRequest request)
    {
        if (request.systemsUserId > 0)
        {
            TheRepository.UpdateUserPreferences(request.UserId, request.usePopups, request.useTheme,
                                         request.recentCount, request.detailsSections);

            return Request.CreateResponse(HttpStatusCode.OK, "Preferences Updated");                
        }
        else
        {
            return Request.CreateErrorResponse(HttpStatusCode.NotAcceptable, "You must provide User ID");
        }
    }

Here's my ajax call:

var request = {
    UserId: userId,
    usePopups: usePopups,
    useTheme: useTheme,
    recentCount: recentCount,
    detailsSections: details
};

$.ajax({
    type: "POST",
    data: request,
    url: "http://localhost:1111/service/User",
    success: function (data) {
        return callback(data);
    },
    error: function (error, statusText) {
        return callback(error);
    }
});

I've tried setting the dataType & contentType to several different things ('json', 'application/json', etc) but the properties of the request object are always defaulted or null. So, for example, if I pass in this object:

var request = {
  UserId: 58576,
  usePopups: false,
  useTheme: true,
  recentCount: 10,
  detailsSections: ['addresses', 'aliases', 'arrests', 'events', 'classifications', 'custody', 'identifiers', 'phone', 'remarks', 'watches']
}

I can see a fully populated request object with the valid values as listed above. But in the Web API controller, the request is there, but the properties are as follows:

  UserId: 0,
  usePopups: false,
  useTheme: false,
  recentCount: 0,
  detailsSections: null

FYI - I'm not doing ANY ASP.Net MVC or ASP.NET pages with this project, just using the Web API as a service and making all calls using jQuery $.ajax.

知道我做错了什么吗？谢谢

UPDATE: I just want to note that I have many methods in this same Web API project in other controllers that do this exact same thing, and I am calling the exact same way, and they work flawlessly! I have spent the morning comparing the various calls, and there doesn't appear to be any difference in the method or the headers, and yet it just doesn't work on this particular method.

我还try 切换到PUT方法，但得到了完全相同的结果-请求对象进入，但没有用正确的值填充.令人沮丧的是，我在这个项目中有大约20个控制器类，而POST在所有这些类中都可以工作……